Nodules and tumors involving the upper cervical spine usually severely damage the vital structures of the atlantoaxial spine and compress the spinal cord, causing severe consequences of paralysis. It is necessary to perform a surgical resection for such patients, and complete the reconstruction and fixation of damaged structures so as to maintain the integrity and stability of the structure of the craniocervical junction region and preserve normal physiological functions.
The atlantoaxial spine is located at the craniocervical junction region, with a special anatomical structure and a deep position, where important nerve center and blood vessels exist nearby, hence it is difficult to perform a resection and reconstructive surgery in a spine surgery. Such difficulties mainly include: (a) The surgical exposure is more difficult; if the atlantoaxial lesion is to be removed, the transoral approach will be necessary, but if the lesion is larger, or the range of the reconstruction and fixation is relatively wide, you may need to implement an invasive surgical approach, such as a lower jawbone sacrotomy with larger wounds; however, this surgical exposure often requires the cooperation of a dentist. (b) The risk of the surgical operation is high; as we know, the spinal canal of the atlantoaxial spine contains the cervical spinal cord and the medulla oblongata at high level, so the excision of lesions requires superb surgical techniques, any slight carelessness would cause damage to the medulla oblongata, leading to a risk of paralysis and even death; there are important blood vessels such as the vertebral artery around the atlantoaxial spine, once damaged, it can cause consequences of cerebellar infarction or death. (c) After lesion removal, the reconstruction of the spine is particularly difficult; at present, clinically used spinal fixation devices include posterior pedicle screw rods, cervical vertebra anterior plates and so on; however, these fixation devices are mainly designed for the lower cervical spine, and ordinary cervical vertebra titanium plates are not suitable for the fixation of the atlantoaxial spine; and the common titanium mesh is a cylindrical column with the same diameter, thus it cannot meet the reconstruction needs of the complicated anatomical shape of the atlantoaxial spine. Although domestic and overseas scholars have improved implants such as titanium meshes and have applied them to the reconstruction after atlantoaxial resection, deficiencies of application of the improved implants still exist, thus the improved implants can hardly meet the requirements of complicated surgeries; wherein the deficiencies could be fixation difficulties, poor shape matching, high failure rate of internal fixation after surgery, and low fusion rate after surgery.